PDA

View Full Version : PyroCat HD Starting Development Times 20 C



IanBarber
23-Jul-2017, 05:32
I appreciate there is no substitute for doing testing for ones own working environment and I intend to do that.

For a starting point, I have collected data for the following films which I was going to use as a starting point for what I consider to be a normal scene, (No + or - development)

These will be 4x5 sheet film, developed in PyroCat HD (1+1+100) (20C) in a Paterson tank with gentle inversions every minute for 15 seconds.

Has anyone used any of the following films with tank inversion as above, and how close are the times listed below to what you have experienced.



Fomapan 100
9.3 Minutes
ISO 50


FomaPan 200
8 Minutes
ISO 100


TMAX 100
14 Minutes
ISO 50


TMAX 400
11 Minutes
ISO 200


Ilford FP4+
9 Minutes 20 Seconds
ISO 64


TRI-X 320
12 Minutes
ISO 160


Fuji Acros 100
16 Minutes
ISO 50

esearing
24-Jul-2017, 04:42
the pyrocat-hd.com site FP4 @EI 125 70* has 8:30 for rotary + 15% for tray/tank with 30 or 60 second agitations = 9:45.
You also do not need to reduce box speed with Pyrocat, I meter at 100 just so I can do the mental math of sunny 16 to double check my exposure.
My starting point for FP4 at EI100 68* was 11-12 minutes with 10 second agitations every minute. 10 minutes was a little thin for me.
So at 70* and EI 64 (1 stop overexposure) you may be in the ball park. Pyrocat is more sensitive to agitation frequency than small adjustments to time.
You can also reduce part B by 25-30% to reduce base fog/stain. 1:0.7:100 and round up your time to nearest minute.

As I have been experimenting I have found it easier to shoot two sheets of film for the scene - process 1 sheet in what I deem as appropriate (N-,N,N+) for that scene. If too dense or thin adjust time/dilution/agitation for the second sheet.
Your choice of paper will come into play at some point since VC warmtone and matte papers behave differently with pyrocat negatives. Or Scanning only - you may like a thinner less contrasty negative.

IanBarber
24-Jul-2017, 04:52
Pyrocat is more sensitive to agitation frequency than small adjustments to time.

Thanks for the reply.

When you say frequency, are you referring to the intervals between agitation or the length of the agitation.

In your experience what do you find when applying different frequencies

esearing
24-Jul-2017, 05:06
T
When you say frequency, are you referring to the intervals between agitation or the length of the agitation.

In your experience what do you find when applying different frequencies

Both - Pyro (and other developers) builds more density with fresh developer constantly applied, which is why rotary is 15% shorter time, due to constant agitation. If you go to two or three minute cycles with 15 second agitation you will see a difference.

One other experiment for control purposes: try the two bath method for a single sheet and normal scene. This gave me what I consider a normal negative that has the slightly more contrast look that I like.
And if in the mood to really see differences over/under expose +/- 2 stops and process normally to gauge highlight compression and shadow details. If using roll film bracket in 1/2 stops to +/- 2stops to see its effects on over/under exposure.

IanBarber
24-Jul-2017, 06:16
Other than N development, have you tried placing the high values above Zone 10 and then used extended times and minimal agitation

jp
24-Jul-2017, 09:45
For Tmax 400 that's probably accurate. I use the film at 400 and have a longer development time.. 14 minutes with 10s of agitation per minute, 1 minute at the start.

IanBarber
24-Jul-2017, 10:02
For Tmax 400 that's probably accurate. I use the film at 400 and have a longer development time.. 14 minutes with 10s of agitation per minute, 1 minute at the start.

Thanks JP